When you watch the video clip (see above) take special note of the Pressure Jetâ€™s startup sequence. If it sounds like it starts instantly, thatâ€™s because it does! Luc and Viv can provide you with details of how and why they automated the process for their test stand and industrial use. However, automation is not necessary to start a properly built Pressure Jet. You simply hit the spark, open the fuel valve to about 50 PSI, it starts, then you let it warm up for a few seconds and youâ€™re ready to go.

Because of the fuel system and intake design, it is also possible to throttle the engine over a wide range of stable operation. Since it runs on liquid propane, the length and size of the fuel line, after the throttle valve, does introduce a bit of a delay in throttle response. Just as with most things you quickly get a feel for it after a few seconds of working with the controls.

Woops, almost forgot. Check out the crowdâ€™s reaction. The second angle was shot after a few seconds of running and a bit of a crowd has already gathered. The ones that donâ€™t already have in / on ear protection have their fingers in their ears and on the sweep you can still see people walking toward the engine. Happened every timeâ€¦

Will try to post a few more pictures later, including one of the Chinese.

Allow me to answer this one, being an ex-pilot my self and a Canadian.

If your glider, using any engine type you can think of, is human piloted, you then have to comply with MOTC (Ministery Of Transportation of Canada) rules and regulations, meaning having a licence, comply with safety regulation and certifications.

Hope this answer your question.

Thanks, Luc, right on the target. How to start the application procedure of converting a glider to a powered one ? For me, this could be 10 times harder than technological problems.

Seems you guys had a lot of fun there.
Doesn't the one photo, where you are sitting in the aircraft, depict the gleam in your eyes?

Oh, Viv and Luc, that's a nice and very professional test or demonstration setup. And a pretty Steve-sized truck...well, I just learned, everything is bigger in northern America...[/quote]

Test stand is the MK2 thrust stand, full data aquistion of temperature pressure and thrust, thrust is wide band and will resolve the thrust from single bangs and harmonic content of the thrust signal, will also read the negative thrust from the tailpipe cold air suck back in between combustion cycles.

Mass compensation is easy to calculate as the engine only moves 1 microinch per 11.5 Lbs of thrust up to plus or minus 500 Lbs.

What? â€¦
Could you repeat that?
One more timeâ€¦
A little louder pleaseâ€¦

OK, BUSTED!
Youâ€™re right, no hearing protection on that run.
Not a mistake I plan to make again anytime soon.

Typically I am the hard ass about safety and I did wear a heavy duty set of protectors almost every time the engine ran. Especially when up close. What you saw in the picture of my run was the result of my rush to play with a new toy. When Luc and Viv offered to let me run the engine, I had no thoughts of giving them time to change their minds. At startup and warm up I still had no thought of hearing protection, but as soon as she kicked into sonic lock, and the thrust started to build, I remembered. I did put a finger in one ear most of the time. It was particularly loud on that side, probably because of a reflection coming from the hanger next door. At least the runs were short.

Additionally, max SPL comes at a 45 degree angle off the tail. There was a fence on one side and mostly behind. We also did our best to keep people away from the direct exhaust blast on the other. A surprising number of the attendees came to the air show with ear protection (often just plugs) and most others were smart enough to put fingers in their ears when anywhere near the engine.

NOTE TO SELF AND OTHERS:
Wear hearing protection at ALL times when working with, or watching, Pulse and conventional Pressure Jet engines!

Considering the high SPL levels, (measured up to 155db) a combination of both ear plugs and hard shell protection is advised as individual devices only have attenuation range of 23db to 33db.

Sign language is a wonderful technology, but not one I would recommend that you take up by necessity.

I remember some rock star recounting how he was playing his guitar and standing next to a bank of speakers. All of the sudden he felt something "go" in one ear. And then, as suddenly, he had lost all hearing in that ear. It didn't come back.
I think we all have gone without adequate ear protection from time to time when running a pulsejet, but it's just not a good idea.
And in today's world, you never know someone might sue you for partial loss of hearing or something if you blast them with 135 dB.
When they demonstrate nitrogen triiodide in a chemistry classroom, they make students wear ear protection, what fun is that if you can't hear the real noise? But I guess it's safety first, the old days/ways are rapidly changing.
Mark

Dave,
I didn't mean to sound so looming in my last post. I've taken some far more foolish risks with my pyrotechnic tinkering. I'm lucky to be unscathed and still have all my fingers and eyesight. Just seems most things that are fun have some element of risk, no free lunch. I'm sure you guys didn't risk anyone's hearing really, but still there are those occasional few who don't even bother to put their fingers in their ears. I've actually run a pulsejet and had a fellow just stand there not in least interested in blocking out the sound!
Your post was quite humorous and witty, a kind sort you are.
Mark

At startup and warm up I still had no thought of hearing protection, but as soon as she kicked into sonic lock, and the thrust started to build, I remembered. I did put a finger in one ear most of the time.
Dave[/quote]

I've done the finger in one ear when I light my snorkeler. The first whoose is ear piercing using methanol. One hand lights the tip and the other hand/ear nearest the blast zone is the finger in the ear. A woman a few houses down thought I was launching rockets, the tank with pipe attached often flames out after an energetic hiss if conditions aren't right. One time in the fall, I got showered with leaves that were air blasted off the tree when starting my "piglet" snorkeler. It was kind of funny.
Mark

I've never run both at the same time however, I did once connect the two head to head with a 2 inch pipe thread T and to that attached a 2 inch pipe without success.
They will run with at least three different lengths and diameters of pipe, some more fussy or robust than others, a trade-off.
Here's one more perspective after a run, a bit of fire broke out, kind of a scorched board effect commonly happening if you use a board or woody matter for a base. This is an old photo and the forum is probably saying, "oh not that old post again."
The first time I was toying with one of these tanks I was sitting on the back porch with it between my legs, holding it upright by the snorkel. When it caught, I could really feel the heat on my legs and I quickly took to holding it by the feet or mounting flanges. It can really radiate heat if nothing else.
Mark

As promised in an earlier post, attached are pictures of the Chinese. This one was built by Luc and Viv using their 22Ga 321 Stainless Laser Cut Parts Kit and was shown running on their web site: http://www.glc-inc.ca/phpbb/viewtopic.php?t=39

Since I was hanging around their shop for a couple of days anyway, Luc asked it I would like to buff up the Chinese in preparation for the air show. I had a lot of fun doing it, while putting some wear and tare on their equipment and supplies. As we all know, an engine never quite looks the same after being run for a while, but this one still shined up pretty well. To see some to the more intricate laser cut pieces in the flat pack kit, just check out the second picture. Because of the computerized layout, and laser cut accuracy, there was no need for additional fitting. Luc says you just roll and weld, as they did for the one in the picture.

In addition to all the fun I had playing in their shop; Luc and Viv presented me with a Chinese 321 SS Laser Cut Kit gratis! They said the freebie is so I can show how easy the parts go together. Now that I have the Kit, all I need to prove that theory is a TIG welder and some time to do the deed. Thanks again guys.